Photographic developer



Patented July 26, 1938 PATENT OFFICE j PHOTOGBAPHIC DEVELOPER Jens Herman Christensen, Sterrehus, Holte,

Denmark No Drawing. Application October 23, 1935, Serial No. 46,343. In Germany October 2'7, 1934 7 Claims. (CI. 95-88) My present invention relates to a photographic developer and more particularly to a photographic developer for the reversal process.

One of its objects is an improved developer for 5 the photographic reversal process. Further objects will be seen from the detailed specification following hereinafter.

It is known that so-called reversal developers for color-plates or films and cinematograph films generally contain a solvent for silver bromide, such as ammonia, a thiocyanate, a bromide'or the like. For developing screen-plates or '-fllms an ammoniacal developer is almost exclusively used; however, it has disadvantages, the most important of which is that the ammonia evaporates from the developer on prolonged standing so that the developing power rapidly diminishes and is therefore uncontrolled; especially the development must be carried out in nearly com- 2 plete darkness and controlled by time. In view of this disadvantage it has already been attempt ed to substitute for the volatile ammonia a more stable organic base and amines have been used, especially triethanolamine. However, these amines have also disadvantages; apart from the fact that even they are somewhat volatile, although much less so than ammonia, whereby the constancy of a developer is afiected, they are not agreeable to the operator because of their unpleasant smell (methylamine, ethylamine etc.),

and in order to produce an efiect equivalent to that of ammonia they must be used in incomparable greater proportion, for instance, triethanolamine.

The present invention overcomes these disadvantages by using as the solvent for silver bromide an aliphatic polyamine containing in its molecule two unsubstituted amino groups (NH2) such as ethylenediamine, diethylene-triamine,

triethylenetetramine. These bodies may be used alone or in admixture with each other or in admixture with suitable inorganic solvents for silver bromide, for instance an alkalibromide; or they may be added to the developer in the form of a chemical compound, such as an amine hydrochloride or particularly an amine thiocyanate. In this mannerthere are obtained developers of high permanence and, therefore, constant in their action; in their developing properties they .are at least equal to the ordinary ammoniacal developers but are free from the known disadvantages of the latter.

The following examples illustrate the invention:

Example 1.-,Stock solution: 5 cc. of a concentrated caustic alkaline solution of l-hydroxy-l-amino-benzene '75 cc. of ethylenediamine solution, 10 per cent. strength. For developing color-plates, 7 cc. of this solution 10 should be added to 100 cc. of water.

Example 2.-Stock solution:

100 cc. of a concentrated caustic alkaline .solution of l-hydroxy-l-amino-benzene, 25 cc. of ethylenediamine solution, 50 per 15 cent strength, 50 cc. of potassium bromide solution, 10 per cent strength. Add 8-10 cc. to 100 cc. of water.

Example 3.-One of the best known reversal 2o developers containing ammonia has the following composition:

1000 cc. of water 13 grams of para-methylamino-phenol sulfate, I 25 4 grams of hydroquinone,

200 grams of sodium sulfite, cryst.,

5,5 grams of potassium bromide 30 cc. of ammonia of 25per cent. strength.

If desired, without otherwise altering this rec- 30 ipe the ammonia in it may be exchanged for ethylenediamine, or there may be used 40 to 50 parts of an ethylenediamine solution of 50 per cent. strength instead ofthe 30 cc. of ammonia of 25 percent. strength. However, in this case, 35 the ethylenediamine developer must be diluted in use with 4-5 times its'volume of water, whereas the ammonia developer is generally diluted only with three times its volume of water.

Example 4.A metol-hydroquinone developer of the following composition 1000 cc. of water 1,5 grams of para-methylamino-phenol sulfate, 2,5 grams of hydroquinone, 45 36 grams of sodium sulfite, cryst., 18 grams of potassium carbonate, 1 gram of potassium bromide -is mixed with '5 cc. of ethylenediamine solution of 50 per cent. strength. The mixture constitutes 50 a good permanent, concentrated, clear reversal developer giving brilliant results: for use it is diluted with water in the proportion of 1:1.

Example 5 .Stock solution:

100 cc. of a concentrated caustic alkaline solution of 1-hydroxy-4-amino-benzene,

25 cc. of ethylenediamine-thiocyanate solution of 10 per cent. strength, 25 cc. of potassium bromide solution or 10 per cent strength, 25 cc. 01' sodium carbonate solution of 10 per cent strength. Add 22 cc. to 100 cc. of water-for use. Example 6.

.1000 cc. of water 4 grams of para-methylamlno-phenol sulfate 1 gram of hydroquinone, 7 grams of ethylenediamine-thiocyanate, 2 grams oi potassium bromide, 40 grams of sodium sulfite (anhydrous) 30 grams of sodium carbonate (anhydrous). Emample 7.-

1000 cc. of water 7 2 grams oi para-methylamino-phenol sulfate, 0.5 gram of hydroquinone 20 grams of sodium sulfite (anhydrous) 15 grams of sodium carbonate (anhydrous) 1 gram of potassium bromide, 1.5 cc. of diethylentriamine, 10 per cent strength. This constitutes a good developer ready for use. Example 8.-

1000 cc. of water 2 grams of para-methylamino-phenol sulfate 0,5 gram of hydroquinone 20 grams or dry sodium sulfite 15 grams of dry sodium carbonate 1 gram of potassium bromide 2 cc. of triethylenetetramine. Example 9.- 100 cc. of a concentrated caustic alkaline solution oi. 1-hydroiw-4-amino-benzene 10 cc. of a solution 01 ethylenediamine of per cent strength 10 cc. of a solution of potassium bromide of 10 per cent strength. Add 10 cc. to cc. of water for use.

Example 10.--

1000 cc. of water 4 grams of para-methylamino-phenol sulfate 1 gram of hydroquinone 2 grams of potassium bromide 40 grams of dry sodium sulfite 30 grams of dry sodium carbonate 1 cc. of diethylenetriamine 1 cc. of triethylenetetramine.

I claim:

1. A photographic developer for the reversal process comprising a developing agent and an aliphatic polyamine containing in its molecule two unsubstituted amino groups.

2. A photographic developer for the reversal process comprising a developing agent and a mixture of aliphatic polyamines containing in their molecules two unsubstituted amino groups.

3. A photographic developer for the reversal process comprising a developing agent and a salt of an aliphatic polyamine containing in its molecule two unsubstituted amino groups.

4. A photographic developer for the reversal process comprising a developing agent and a thiocyanate of an aliphatic polyamin containing in its molecule two unsubstituted amino groups. 5. A photographic developer for the reversal process containing a caustic alkaline solution of 1 hydroxy 4 amino-benzene, ethylenediamine thiocyanate; potassium bromide and sodium carbonate.

6. A photographic developer for the reversal process containing para-methylaminophenol sulfate, hydroquinone, ethylenediamine-thiocyanate, potassium bromide, sodium sulfite and sodium carbonate.

7. A photographic developer for the reversal process containing 1-hydroxy-4-aminobenzene,

ethylene diamine-thiocyanate, potassium bromide, sodium sulfite and sodium carbonate.

JENS HERMAN CHRISTENSEN. 

